/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    Obfuscate.java
 *    Copyright (C) 2002 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.RevisionUtils;
import weka.core.Capabilities.Capability;
import weka.filters.Filter;
import weka.filters.StreamableFilter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> A simple instance filter that renames the relation,
 * all attribute names and all nominal (and string) attribute values. For
 * exchanging sensitive datasets. Currently doesn't like string or relational
 * attributes.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * @author Len Trigg (len@reeltwo.com)
 * @version $Revision: 6175 $
 */
public class Obfuscate extends Filter implements UnsupervisedFilter,
		StreamableFilter {

	/** for serialization */
	static final long serialVersionUID = -343922772462971561L;

	/**
	 * Returns a string describing this filter
	 * 
	 * @return a description of the filter suitable for displaying in the
	 *         explorer/experimenter gui
	 */
	public String globalInfo() {
		return "A simple instance filter that renames the relation, all attribute names "
				+ "and all nominal (and string) attribute values. For exchanging sensitive "
				+ "datasets. Currently doesn't like string or relational attributes.";
	}

	/**
	 * Returns the Capabilities of this filter.
	 * 
	 * @return the capabilities of this object
	 * @see Capabilities
	 */
	public Capabilities getCapabilities() {
		Capabilities result = super.getCapabilities();
		result.disableAll();

		// attributes
		result.enableAllAttributes();
		result.enable(Capability.MISSING_VALUES);

		// class
		result.enableAllClasses();
		result.enable(Capability.MISSING_CLASS_VALUES);
		result.enable(Capability.NO_CLASS);

		return result;
	}

	/**
	 * Sets the format of the input instances.
	 * 
	 * @param instanceInfo
	 *            an Instances object containing the input instance structure
	 *            (any instances contained in the object are ignored - only the
	 *            structure is required).
	 * @return true if the outputFormat may be collected immediately
	 * @throws Exception
	 *             if
	 */
	public boolean setInputFormat(Instances instanceInfo) throws Exception {

		super.setInputFormat(instanceInfo);

		// Make the obfuscated header
		FastVector v = new FastVector();
		for (int i = 0; i < instanceInfo.numAttributes(); i++) {
			Attribute oldAtt = instanceInfo.attribute(i);
			Attribute newAtt = null;
			switch (oldAtt.type()) {
			case Attribute.NUMERIC:
				newAtt = new Attribute("A" + (i + 1));
				break;
			case Attribute.DATE:
				String format = oldAtt.getDateFormat();
				newAtt = new Attribute("A" + (i + 1), format);
				break;
			case Attribute.NOMINAL:
				FastVector vals = new FastVector();
				for (int j = 0; j < oldAtt.numValues(); j++) {
					vals.addElement("V" + (j + 1));
				}
				newAtt = new Attribute("A" + (i + 1), vals);
				break;
			case Attribute.STRING:
			case Attribute.RELATIONAL:
			default:
				newAtt = (Attribute) oldAtt.copy();
				System.err
						.println("Not converting attribute: " + oldAtt.name());
				break;
			}
			v.addElement(newAtt);
		}
		Instances newHeader = new Instances("R", v, 10);
		newHeader.setClassIndex(instanceInfo.classIndex());
		setOutputFormat(newHeader);
		return true;
	}

	/**
	 * Input an instance for filtering. Ordinarily the instance is processed and
	 * made available for output immediately. Some filters require all instances
	 * be read before producing output.
	 * 
	 * @param instance
	 *            the input instance
	 * @return true if the filtered instance may now be collected with output().
	 * @throws IllegalStateException
	 *             if no input format has been set.
	 */
	public boolean input(Instance instance) {

		if (getInputFormat() == null) {
			throw new IllegalStateException("No input instance format defined");
		}
		if (m_NewBatch) {
			resetQueue();
			m_NewBatch = false;
		}
		push((Instance) instance.copy());
		return true;
	}

	/**
	 * Returns the revision string.
	 * 
	 * @return the revision
	 */
	public String getRevision() {
		return RevisionUtils.extract("$Revision: 6175 $");
	}

	/**
	 * Main method for testing this class.
	 * 
	 * @param argv
	 *            should contain arguments to the filter: use -h for help
	 */
	public static void main(String[] argv) {
		runFilter(new Obfuscate(), argv);
	}
}
